Absorption is a potion from the Nightmare Zone minigame, costing 1,000 reward points per dose. It can only be used while in the Nightmare Zone.

Drinking the potion causes the next 50 damage inflicted on the player to be absorbed, preventing the player from taking damage. Each dose will absorb 50 damage, which stacks with previous unused Absorption damage up to 1000 damage. It will not absorb damage the player inflicts on themselves, such as from overload potions, poison karambwans or dwarven rock cakes.

A good way to boost the effectiveness of the Absorption potion is to use the dwarven rock cake to lower your hitpoints, and flick the Rapid Heal prayer to stop your hitpoints from being restored. This will leave you with only 1 hitpoint, so enemies will only be able to inflict a maximum of 1 damage on you at a time, so a maximum of only 1 damage will be drained from Absorption per enemy hit.